Iminophosphonamide complexes have been known for some time. However, there has been no disclosure that such compounds may be used to polymerize monomers, such as olefins, more particularly alpha olefins such as ethylene and its higher homologues.
BASF's European Patent 0 687 693 A1 (corresponding to U.S. Pat. No. 5,707,913 issued on Jan. 13, 1998) discloses complexes with following structure used as polymerization catalysts: ##STR1##
where, M represents a metal from IIIb, IVb, Vb or VIb of the periodic table of elements or a metal from the lanthanide group, X is a negative leaving atom or a negative leaving group, which may be identical or different if (n-m)&gt;1, R.sup.1, R.sup.2 and R.sup.3 are each a C-organic or Si-organic radicals, n is the valence of M in the metal complex, and m is from 1 to 5, with the proviso that n-m=0. The metal complex is activated with an activator in a molar ratio of activator to metal complex from 0.5:1 to 10,000:1. While the complex of the BASF patent to some extent looks similar to those of the present invention the ligands do not contain a phosphorus atom between the two nitrogen atoms of the ligand. Accordingly, the BASF patent does not teach the subject matter of the present invention.
Exxon's U.S. Pat. No. 5,318,935 discloses complexes having the following structure: ##STR2##
wherein M is zirconium, hafnium or titanium, N is a nitrogen atom having three substituents; each "X" is independently, any univalent anionic ligand selected from the group consisting of halide, hydride, straight, branched, or aromatic hydrocarbyl radicals, alkoxide, aryloxide, amide having singly or multiply branched hydrocarbyl radicals having between 3 and 30 carbon atoms or, arylamide, phosphide and arylphosphide. "T" is a covalent bridging group selected from the group consisting of unsubstituted hydrocarbyls and substituted hydrocarbyls containing a Group IV-A or VI-A element; and each "R" is independently or any radical containing a Lewis basic functionality; and alumoxane as cocatalyst. The reference teaches away from the subject matter of the present invention as the bridging group between two nitrogen atoms does not include a phosphorus or arsenic atom required by the present invention.
J. Organomet. Chem. 371 (1989) C40-C44 discloses the synthesis of complexes having the formula: ##STR3##
The reference does not teach the use of the complexes for the polymerization of olefins.
J. Organomet. Chem. 469 (1994) C27-C30 teaches the synthesis of the following complex: ##STR4##
The reference does not teach polymerization of olefins using such a complex.
The following structures have been disclosed in J. Chem. Soc. Dalton Trans 1989, 2173. ##STR5##
The paper contains no polymerization data, nor does it suggest that such complexes may have utility as polymerization catalysts for olefins.
J. Organomet. Chem. 414 (1991) 327-335 discloses the synthesis of the following complexes: ##STR6##
Again no polymerization data is given in the paper nor is there any suggestion that the complexes would be useful in the polymerization of olefins.
The present invention seeks to provide a novel process for the polymerization of olefins using iminophosphonamide complexes with transition metals.